土体干缩裂缝发育演化规律试验研究
Experimental Study on the Development and Evolution Patterns of Shrinkage Fissure in Soil
DOI: 10.12677/ag.2025.159122, PDF,    科研立项经费支持
作者: 刘 涛*, 单以春#, 顾春生, 张 丽, 李 伟：江苏省地质调查研究院，江苏 南京；自然资源部地裂缝地质灾害重点实验室，江苏 南京
关键词: 地裂缝；失水干缩；成因机制；断裂韧度；基质吸力；Ground Fissure； Water Loss and Shrinkage； Formation Mechanism； Fracture Toughness； Matrix Suction
摘要: 土体失水干缩是地裂缝形成演化的重要因素。通过室内试验方法，本文开展了不同成分土体的干缩开裂试验，对土体的开裂形态、干缩裂缝的形成演化阶段进行了划分，总结了土体成分、含水量变化对其干缩裂缝的发育演化规律，对土体成分、含水率与土体断裂韧度关系进行了探究。试验表明：1) 根据裂缝的开裂形态与速率，可将干缩裂缝的发育阶段划分为失水收缩、快速开裂、干缩停滞三个阶段。2) 干缩试样中，主裂缝宽度随黏土含量递增；次生裂缝的长度和数量则随黏土含量的增加表现出先升后降的变化，且干缩造成的主次裂缝呈现垂直关系。3) 失水干缩过程中，土体断裂韧度受含水率及黏土成分的影响显著。试样基质吸力随含水量的降低而增加，含水率低于12%左右时，断裂韧度随含水率的降低而减小。结论：土体失水导致基质吸力增大，引发体积收缩和能量积累，最终通过开裂形式释放能量，基质吸力随含水率的降低而增加是干缩开裂的诱发因素；非饱和试样的断裂韧度随含水率的降低而降低，导致土体抵抗断裂能力减弱，断裂韧度的降低是干缩裂缝的重要影响因素。
Abstract: The water loss and shrinkage of soil play a great important part in the evolution of the ground fissures. In this paper, through laboratory test method, the dry shrinkage cracking test of soil with different components is carried out; then the cracking morphology of soil mass and the formation and evolution stages of dry shrinkage cracks are divided. The development and evolution patterns of dry shrinkage cracks influenced by soil composition and moisture content changes are summarized. Furthermore, the relationship between soil composition, moisture content and soil fracture toughness is discussed. The results show that: 1) According to the shape and rate of cracking, the development stage of dry shrinkage cracking can be divided into three stages: dehydration shrinkage, rapid cracking and dry shrinkage stagnation. 2) The width of the main crack formed by the dry shrinkage of the sample increases with the increase of clay content; the length and number of secondary cracks increase first and then decrease with the increase of clay content, and the primary and secondary cracks caused by dry shrinkage show a vertical relationship. 3) In the process of water loss and shrinkage, the fracture toughness of soil is significantly affected by water content and clay composition. The matrix suction of the sample increases with the decrease of water content; in addition, when the water content is less than 12%, the fracture toughness decreases with the decrease of water content. Conclusion: The essence of water loss and shrinkage crack is the process of volume shrinkage and energy accumulation caused by the decrease of soil moisture content and the increase of matrix suction, and it is also a process of releasing energy in the form of cracking. The increase of matrix suction with the decrease of water content is the inducing factor of dry shrinkage cracking. The fracture toughness of unsaturated samples decreases with the decrease in water content, resulting in the weakening of the fracture resistance of soil. The reduction of fracture toughness is an important factor affecting dry shrinkage cracking.
文章引用：刘涛, 单以春, 顾春生, 张丽, 李伟. 土体干缩裂缝发育演化规律试验研究[J]. 地球科学前沿, 2025, 15(9): 1317-1327. https://doi.org/10.12677/ag.2025.159122

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